diff --git a/src/_pytest/compat.py b/src/_pytest/compat.py
index 2f5a4c863f9..72c3d0918fb 100644
--- a/src/_pytest/compat.py
+++ b/src/_pytest/compat.py
@@ -309,5 +309,6 @@ def __call__(self) -> bool:
 def running_on_ci() -> bool:
     """Check if we're currently running on a CI system."""
     # Only enable CI mode if one of these env variables is defined and non-empty.
+    # Note: review `regendoc` tox env in case this list is changed.
     env_vars = ["CI", "BUILD_NUMBER"]
     return any(os.environ.get(var) for var in env_vars)
diff --git a/tox.ini b/tox.ini
index 2e91ddcb2d6..70b439f7573 100644
--- a/tox.ini
+++ b/tox.ini
@@ -171,6 +171,10 @@ commands =
 setenv =
     # We don't want this warning to reach regen output.
     PYTHONWARNDEFAULTENCODING=
+    # Remove CI markers: pytest auto-detects those and uses more verbose output, which is undesirable
+    # for the example documentation.
+    CI=
+    BUILD_NUMBER=
 
 [testenv:plugins]
 description =